Chapter 10 - Scratch-built Pipe, Round 1
Some time ago, circa 2014, I built a rolled-cone pipe for a Suzuki K15. 26-gauge mild steel, thin enough to cut with tin-snips (0.01875" or 0.47mm) and roll by hand on a table with a piece of round stock. Main purpose of that project was to force myself to improve my non-existent TIG skills. Ended up with this, has a tapered header btw:
For the General, I intend to do the same. Since it's a more racy-looking bike than the K15 was, I hope to take some inspiration from road race bikes - so either a simple swoop downwards under the engine, or perhaps a sort-of under-the-seat exhaust exit.
Mocked up a first iteration in paper, copying the dimensions of the Doma pipe I've currently got mounted on the bike:
This time around, I'm planning to use 22ga steel for a little more durability. Thin is good for a single speed - pipe temperature changes more rapidly. It will cool down at a stop, acting like a longer pipe, and heat up quicker once you get going, acting like a shorter pipe. It might not make a huge difference, but certainly won't hurt, at least as a thought exercise. EngMod has the ability to model this (pipe wall temperature), so I may run it through the sim to see if I'm assuming correctly.
This particular pattern, though, isn't exactly what I was going for. To clarify, the idea is to make it end-bleed, and for this layup, the idea was to end up with a semi-under-seat exit. Having since built the footrests, though, they are very convenient for mounting a rear pipe mount, and I like the low-down horizontal stinger/baffle layout that I've got going on with the Doma pipe.